Recaulking Teak Strip Decking - IG36

I`m close to starting this, using either Sikaflex 290DC,or Deckflex MSP100,as the caulk,with matching primer.
The existing caulk is in poor condition, letting water under it. To remove it (some will come out very easy) and clean the channel, I`m thinking of using a router, maybe making the groove a little deeper to give better attachment and compensate the loss of thickness of the teak occurring over time.
I don`t own,and have never used,a router.Is this a good way to go,is there a more suitable power tool?
Alternatively I can dig the old caulk out using a blade down the sides and a 1/4 inch chisel or screwdriver to scrape out. I did that fairly successfully in a few specific areas, masking the edges before pumping in the caulk.
I judge the condition of the teak just good enough to warrant doing the job. The decks do not feel soft anywhere.
Deckflex say that after curing, sand the whole deck, caulk and all,to a flat surface.
Advice,tips,experiences,would be appreciated.
BruceK, Sydney Australia.

First of all, don't use the caulks you listed. There is only one teak deck caulk on the planet worth using and that is TDS (from Teak Decking Systems). It's what manufacturers like Grand Banks use on their boats at the factory. We have been using TDS since it became available retail in the early 2000s. It is FAR superior to any of the other caulks.

Second, unless you construct a guide rail don't use a router. If you try to freehand it it will get away from you and your deck grooves will end up looking like snakes. We had our main deck completely regrooved and recaulked some ten or eleven years ago. The very experienced shipwright who did the job contemplated using a router but in the end decided it was too risky and constructing guides for it was too much hassle. So he removed the old caulk by hand (which is quite easy to do in my experience) and used a series of special planes and chisels to recut the grooves manually. The end result was very nice.

The only downside was at the time he did the job, TDS was not on the market yet. So he used the caulk that was common at the time. It's held up okay but there are seams that are starting to pull away from one side or the other on the side and aft deck. As I repair or replace them I am using TDS and what a difference in longevity and resistance to UV, wear, etc.

Make sure you use bond-breaking tape in the bottom of the grooves before you apply the new caulk. If you don't the caulk will adhere to the sides of the grooves and the bottom with the result that as the boards work--- and they do very slightly as well as expand and contract with temperature and moisture--- the caulk will not be able to flex properly to maintain a good seal to the sides of the groove. Eventually the caulk will pull away from one side or the other of the groove and you'll be back to getting water under the planks again.

There is a ton of information on recaulking teak decks on the Grand Banks owners forum Grand Banks Owner's Resources. I think you have to join to access the archives but joining is free. Almost all GBs have teak decks so they are something GB owners know a lot about the care and feeding of. I love teak decks but they do require the correct procedures if one is going to regroove and reseam them. Done incorrectly, and the problems will be back very quickly. The proper techniques are not difficult to learn but they have to be followed or the result will not be satisfactory or very long-lived.

I have to redo the seams in the teak "pad" that is the landing on top of the aft cabin for going to and from the flying bridge. The sealant is shot--- it's probably the original--- and the boards have worn to the point where the bottoms of the grooves in places are even with the tops of the planks. But there is enough wood thickness to let me regroove it this one time.

I will remove all the old sealant by hand using an X-acto knife. I plan to recut the grooves with a router BUT..... all the grooves are dead straight, there is plenty of room to work on them (no bulwarks or cabin sides in the way) and I am going to construct an adjustable router guide out of some heavy brass strip stock I have that will fasten down with the deck screws in the adjacent plank.

Fein makes an attachment for their multitool specifically designed for removing the caulk. It works great.
I won't get into the what caulk to use debate but you need to get the deck dry out before re-caulking. Good luck with that.

... There is only one teak deck caulk on the planet worth using and that is TDS (from Teak Decking Systems)...

...Make sure you use bond-breaking tape in the bottom of the grooves before you apply the new caulk....

Click to expand...

I'll second the vote on TDS. We re-caulked the entire decks and replaced the teak/re-caulked the teak on the house with TDS on our last boat. When we sold the boat 5 years later every seam was still tight. On the house, we bedded the teak in TDS (no screws) then went back and caulked the seams.

We never used bond-breaking tape. We were told we didn't need it. Talk to TDS. They probably do more decks than any other company out there.

We re-cut the groves in the deck using a 4" Makita hand circular saw with a dado blade that we made by putting to blades together. We re-cut the short cuts by hand with a chisel. We cleaned the groves using the a bent handle from a large file.

An other advantage of the TDS is no primer other than acetone. Good luck.

The first mate and I did our complete flybridge, part of the aft deck, and other "suspeicious" looking seams within the past 2 years.
TDS 440 is what we used. E mail them and they will send instructions. However, I ordered the amount of caulk they recommended and it was almost twice what I used. It has an expiratin so don't order too much.
Personally, forget the router and the feintool. I have both, but choose to use the boatlife hot knife, avalable thru Defender (and others I'm sure). The hotknife makes childs play out of getting the old coulk out. The issue is the blade is radiused so you need to go inafter the knife and use a bent screwdriver tool that is "slightly sharpened" to scrape out the sides and bottom of the groove. Easy task.
Then 80 grit (or so) sanding belts by hand to clean the sides and bottom of the grroves. I'm talking a few quick swipes and they are clean.
Vacuum, then wipe the grooves with acetone or xylene to clean the wood.
Tape and caulk. Pic of tools used

You do not need to use any power tool to re caulk the deck. I would recommend doing a small area at a time as the caulking for teak deck is really messy. However, before it dry you can clean up with just paint thinner. Be sure to have a lot of paper towels. Also you can do the problem/worst areas first and later go back an do the other areas. An easy way to tell if the caulking is not holding is to wet down the deck and watch it dry. The last strips to dry leaving a water/moist strip along the caulking is a good indication, or if you can slip a knife between the caulking and the strip.

However before re caulking make sure the teak strip is properly fastened. If bungs/plug are missing pushed up is an indication the screw is not holding. The bungs/plug might look ok but if the deck is not flat or you can feel the board move. Re caulking a teak deck that is not securely fastened is a waste of time.

To get an old fastener screw out can be a pain. The best tool is an electrician screw driver. The blade is slit so it can become wider which allows it to grab onto the screw and pull it out. It also come in very hand taking/out screws that are in small hard to reach areas. They are sold at most commercial electrical stores, not lows/home. I buy mine at North Coast Electric in the Seattle area.

Take a carpet/hook nose knife and slice down both sides of the caulking as close as possible to the teak stripe, with flat screw diver as narrow as the groove, pry/strip out the old caulking, with the side of the flat head screwdriver ream out the old caulking remaining and any rotten wood, sand the groove. Tape both sides of the groove. Might want to tape a tad bit wider as the tape tends to pull up the fresh caulking.


The caulking I have used that has lasted for 10+ years is Boat Life Teak Deck Caulking that is sold at most marine stores. Anyway you do not need a power tool that can cause damage to your deck.

Larry M said:

We never used bond-breaking tape. We were told we didn't need it. Talk to TDS. They probably do more decks than any other company out there.

Click to expand...

I did, when we first heard of them. I called them to learn more about their product. They even sent me two free tubes of TDS to try out. And they were the ones who told me to be sure to use bond-breaking tape. If you don't, they said, the seam will eventually fail on one side or the other. This was many years ago so perhaps they've changed their tune. Or maybe they figured out that if you don't use the tape you'll be back buying more TDS in a few years so they'll sell more product.

In any event, the tape is recommended by every shipwright and retired shipwright and knowledgeable deck person on the GB owners forum, and the consequences of not using it are so logical and obvious that we have used it in all our seam repair, including when the entire main deck was regrooved and recaulked. In fact it was the shipwright who did that job that first told me about the tape and why it's essential. And it's such an easy step it's puzzling why anyone would advocate not using it since its benefit is so apparent.

If your "teak deck" is real , go for it.

If the teak is an overlay ,( Typical TT) the leak problem frequently is the goop UNDER the teak around the deck fastening, has died with age.

Tightening a screw or a new bung does not get goop under the plank.

Yes doing a first class re caulking might stop the leaks , just as a good tarp would.

But its not forever if it does work..

FF

Don't use a router, it'll get away from you and carve out places you don't want carved out. The Fein has a U shaped blade which works great. I also second the TDS caulk. I've used it for years without a bond breaker with no problem.

I have a large Word document where I've captured lots of posts about how to repair teak decks and bungs. If anyone is interested just send me a PM with your e-mail.

The use of bond breaking tape in a re-grooving is mandatory. The wood is only grooved part way down. Below the goop, the wood moves. Without the tape, the movement will cause the goop to separate from one side of the groove. With the tape, it will be able to move with the movement of the wood and stay secure to the sides. The TDS advice that it is not necessary only applies to the more modern method of putting a teak deck together in the shop, where the black goop goes all the way through, and the whole prefab section is then laid on a bed of black goop.

" koliver:The use of bond breaking tape in a re-grooving is mandatory. The wood is only grooved part way down. Below the goop, the wood moves. Without the tape, the movement will cause the goop to separate from one side of the groove."

I see the sense of that. So far I can`t find TDS products in Australia which may limit choice of caulk, though tape might be available industrially I read it`s a polyethylene tape but simple masking tape works too. The tape is to not stick well to wood so the bottom of the caulk stays unattached. Masking tape is good at that. Thoughts? BruceK

The shipwright who taught me how to repair and replace deck seams uses 3M auto stripng tape. It is somewhat similar to masking tape but its backing is smooth, not textured, which our shipwright friend said is important. It comes in several widths one of which matches our deck grooves-- 1/4"-- exactly. I roll it out into the groove and then use a 1/4" wide roller to stick it to the bottom of the groove.

If they can get TDS in Singapore and Malaysia (Grand Banks uses it in their yards there) I would think you can get or order it in Australia.

Bond breaking tape looks like cotton shoelaces.

The advantage of the auto striping tape, according to our shipwright friend, is that it is very thin and so does not take up much of the depth of the groove. Thicker materials can work just as well in terms of preventing a bond to the bottom of the groove but they reduce the amount of sealant that can be put into the groove. So says he, at any rate.

Actually the all-time best tool for removing stubborn screws was revealed to me by the shipwrights on the Grand Banks owners forum. It's a brace, or bit and brace if you will. The old fashioned hand drill with the "crankshaft" shape.

They can be found fairly reasonably at antique stores that carry old tools. I bought mine in La Conner, a waterside town that has fashioned itself as something of an antique mecca.

The problem with the brace is finding bits for it, particularly screwdriver bits. The bits for these tools are the ones that have the square tapered section at the top of the rod. This section fits into the jaws of the brace. A conventional bit or driver made for today's drills won't fit securely. Nobody makes them new anymore so you have to search the internet--- eBay and the like--- or the antique stores. I got a pair of slotted screw bits on eBay.

All the original screw fasteners on our '73 GB are slotted. The nice thing about a brace is that, particularly for the deck, you can put a tremendous amount of pressure on it to keep the bit from jumping out of and damaging the head of the screw.

The other thing some of the GB restorers swear by is an impact screwdriver. The small battery powered kind. But so far I've had very good luck with the brace.

I have used the Fein multitool with the hook shaped blades to remove the old caulk. Then sand the inside sides of the groove and clean with acetone. I used the fine-line masking tape that Marin mentioned as a bond breaker. To save cleanup time, I masked both sides of the groove with 3m masking tape. Apply the TDS caulk with a caulking gun. Smooth the caulk with a flexible putty knife. Pull the tape before the caulk sets up. A powered caulking gun would help with getting a smooth bead and prevent hand fatigue.

The TDS web site has instructions, as I recall.

Can someone describe what bond breaking tape does? Do you use it IN the groove? Not sure I understand the application here.

The theory is that the tape when applied to the bottom surface of the groove will allow the planks to expand/contract without pulling on the caulk in a third direction, thus increasing the tendancy for the caulk to break the bond on the sides.

If you send me an e mail to
jleonard@usa.norgren.com I will send you the info TDS sent to me that explains and shows pictures.

GonzoF1 said:

Can someone describe what bond breaking tape does? Do you use it IN the groove? Not sure I understand the application here.

Click to expand...

There used to be a little illustration on a Lifecaulk tube of sealant--- or on the cardboard packaging--- of how the sealant in a groove can flex. It's an exaggerated cross-section drawing, but the "block" of sealant is bent into a shallow S curve by the difference in height of the adjacent planks. This is to illustrate how deck planks can work with pressure (you walking on them), moisture content, temperature, the boat flexing, and so on. If the sealant was adhered to the bottom of the groove as well as the two sides, it would not be able to make this S-bend and eventually it would pull away from one side of the groove or the other and moisture would be able to get down under the boards.. The tape prevents the sealant from adhering to the bottom of the groove.

Incidentally, I have found that Lifecaulk is absolute crap for deck seams. I've tried it and it has a very short life and fails fairly quickly. I have not been impressed with any of Lifecaulk's products. The only use I have for it any more is when I reset a deck screw. After re-boring and countersinking the screw hole I dip the very end of the screw in black Lifecaulk to help form a seal around the threads when I install the screw (another shipwright technique I was taught). But based solely on our experience, I never recommend Lifecaulk for anything other than the screw-tip thing. We use TDS for deck work and Sikaflex and Dolfinite for everything else.

And NEVER silicone. Silicone is Evil in a Tube.

Marin said:

And NEVER silicone. Silicone is Evil in a Tube.

Click to expand...

I could not agree more. Either the builder or a PO caulked and bedded EVERYTHING on the exterior of our boat with the darned stuff. It has mildewed (black, yucky) and failed everywhere.

Bit by bit I am trying to get rid of it all. Just spent a week removing it from around 10 windows. The stuff is even evil to remove.

GonzoF1 said:

Can someone describe what bond breaking tape does? Do you use it IN the groove? Not sure I understand the application here.

Click to expand...

Thank you one and all for the helpful contributions to this project.Having previously done some small patch repairs to the caulking,I think the most challenging part of the job is deepening the grooves without doing violence to the teak.

My (perhaps) simplistic view of bond breaker tape is it provides a base for the caulk pumped into the groove but allows the caulk to "float" free of the groove base,so the caulk moves with and stays attached to only the sides of the groove.

TDS responded to an email sent to an address I found via internet search. They have just one agent for all Australia,located in Perth, Western Australia, opposite side of the country from Sydney.The usual chandlers do not stock their products.They sent useful information on preparation and product usage I am happy to share if you PM me with email address.They say that unlike Deckflex and Sika caulks,their product needs no primer for teak application, provided the seams are properly prepared.
BruceK

BruceK said:

They say that unlike Deckflex and Sika caulks,their product needs no primer for teak application, provided the seams are properly prepared.
BruceK

Click to expand...

True, but the inside of the groove needs to be wiped down with acetone just prior to appying the TDS. The acetone removes any surface traces of oil which permits a better bond between the sealant and the wood.

Very glad I stumbled on this thread as I'll be getting to re-caulking seams soon. I suppose a ships supply would have the tape ?

If you elect to use the 3M auto striping tape as we do, you can get it at stores that sell professional auto painting supplies.

Bugmon said:

Very glad I stumbled on this thread as I'll be getting to re-caulking seams soon. I suppose a ships supply would have the tape ?

Click to expand...

The chandlery supply chains in Australia don`t seem to stock it; in USA TDS stockists should have it and your local auto parts shop should have decorative auto pinstripe stripe tape which works (see Marin`s post).
When I searched the tape on the net,one hit was specifications for a building job authorizing using ordinary masking tape as bond breaker tape. Problem might be finding 1/4inch masking tape.
Logic suggests that once the caulk cures without bonding to the base of the channel, it never will and the tape has done its job. Logically,logic is always right,but......
BruceK

I need to do a make-over on our foredeck's teak. It is the only remaining original teak decking, side & cockpit decks having been removed, deck epoxy'd and new teak glue-fixed over.

But I have some screws that have lost their bungs and the last sanding went close to the tops of these. I understand screws can be removed and epoxy 'plugs' injected in their place (then capped off with bungs)...anyone with experience of doing this?

Two independent shipwrights have concluded the deck is in sufficiently good condition that replacing at least the visible screws this way, then setting up a guide and router-ing out the caulk lines before re-caulking, is the way to go.

Aquabelle said:

But I have some screws that have lost their bungs and the last sanding went close to the tops of these. I understand screws can be removed and epoxy 'plugs' injected in their place (then capped off with bungs)...anyone with experience of doing this?.

Click to expand...

We have done all the maintenance on our 39-year old teak deck ourselves for the 14 years we've owned the boat. The one exception is we hired a shipwright to regroove and reseam the main deck a few years after buying the boat. Everything else--- resetting and resealing deck screws, replacing plugs, repairing or replacing seams---- we do ourselves.

It's pretty easy work once you understand the techniques and have the right tools.

There have been how-to discussions on this forum in the past and there is a ton of information on the care and feeding of teak decks on the Grand Banks owners forum Grand Banks Owner's Resources since most GBs have them. You have to join the forum to access the archives I think, but it's free.

If you have specific questions on the techniques, tools, or materials feel free to PM me if you like.

Yes, I'm bringing this one back to life! Lots of good information right here.

My Questions:
- I've read to not get any solvents near the teak...how do you get the solvent into and to clean the seams? with a q-tip?
- bonding tape - only on the bottom of the seams?
- deck must be dry - so being clean as well is an impossibility?
-How can I be sure the deck is dry enough? The acetone cleans the seam and the side of the teak planks?
- why do some people route? Is it only if the seam is deformed?

It is said to do small sections at a time, does this mean you do not need to keep a wet edge?

Our deck seams are starting to separate. Bungs are in great shape. No signs of leaking, just need new caulking.

Thanks Ya'll!!

Solvent won't hurt the teak--- I clean the grooves prior to putting in bond breaking tape and then new sealant with a rag and acetone.

The bond breaking tape should only be applied to the bottom of the groove. This is to prevent the seam sealant from adhering to the bottom of the groove. If it does, the sealant will pull away from one side or the other of the groove sooner rather than later as the planks work and expand and contract with temperature and moisture. You want a bond only on the opposite sides, not on the opposite sides and the bottom.

The deck is dry when the deck is dry. It's just something you have to learn to judge.

The reason seams have to be routed or regrooved is if the planks have been sanded too much or treated with teak cleaner/restorer (which does the same thing as sandpaper only chemically) and there is not enough wood thickness left for an effective groove. So the groove needs to be cut deeper. Obviously there is a limit to how much this can be done, and when that limit is reached the deck planks must be replaced or removed. If the owner elects to remove them something else must be put in their place, usually a couple of layers of fiberglass followed by a non-skid surface.

This is why sanding, powerwashing, chemical cleaning or "restoring," scrubbing with the grain, etc. are all Very Bad Things to do to a teak deck because all of them make wood cells go away and wood that goes away never comes back.

The main objective in caring for a teak deck--- and we've brought a very bad one back from near failure and have been taking care of it now for the last 14 years--- is to a) keep it clean, b) maintain the inegrity of the seams because a failed or separated seam is how moisture gets under the planks, and c) replace missing deck screw plugs as soon as practical as this is another way moisture can get down under the planks.

I was irresponsible for the thread you revived. After much research I decided my decks could not be, had them removed, did the bow section with non skid on 2 layers of glass, the rest in new teak glued over 1 layer of glass;the outer strip is screwed to provide a means to fix the inner planks. I watched the work done, the teak part was s-l-o-w. Fortunately, your decks sound repairable.
Additional to Marin`s response:
Routing the groove requires fixing and controlling the router/trimmer, can`t be done freehand, requires expertise.
The groove should be primed with the sealant makers primer.
The edges of the groove can be taped with masking tape and the groove slightly overfilled. When completely dry,sand the lot smooth.
You do short distances of sealant, in sections, so your knees don`t get stuck in wet sealant. Think of working along a side deck, doing all 5 or 6 grooves as far as you can reach, repeating and repeating.